linux-kernel - Re: [PATCH v2 0/3] mfd: sprd-sc27xx: Move poweroff/reboot support to the parent MFD driver

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Message-ID: <4508c3b6-ba93-4219-8fc6-e3005d35a426@linux.dev>
Date: Fri, 21 Nov 2025 10:29:59 +0800
From: Cixi Geng <cixi.geng@...ux.dev>
To: Baolin Wang <baolin.wang@...ux.alibaba.com>,
 Otto Pflüger <otto.pflueger@...cue.de>,
 Lee Jones <lee@...nel.org>, Orson Zhai <orsonzhai@...il.com>,
 Chunyan Zhang <zhang.lyra@...il.com>, Mark Brown <broonie@...nel.org>,
 Sebastian Reichel <sre@...nel.org>
Cc: Rob Herring <robh@...nel.org>, linux-kernel@...r.kernel.org,
 linux-spi@...r.kernel.org, linux-pm@...r.kernel.org,
 Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH v2 0/3] mfd: sprd-sc27xx: Move poweroff/reboot support to
 the parent MFD driver


On 19/11/2025 14:33, Baolin Wang wrote:
> CC Cixi.
>
> On 2025/11/11 03:08, Otto Pflüger wrote:
>> Registers for powering off the system are present in all SC27xx-series
>> PMICs, although their locations vary between the specific PMIC models.
>> On systems using these chips, the PMIC can always power off the system
>> and is usually the only chip capable of doing this. Similarly, the PMICs
>> (except for SC2731) contain a reset register that can always be used to
>> restart the system.
>>
>> There is an existing sc27xx-poweroff driver, but it currently only works
>> on SC2731 and is not probed anywhere since it is missing an OF match
>> table and is not instantiated by the MFD driver. Reboot for SC2731 is
>> implemented in drivers/spi/spi-sprd-adi.c, which is not really an
>> appropriate location for PMIC-specific code.
>>
>> Since a separate device tree node for the poweroff support would not
>> provide anything useful (see [1]) and passing platform-specific data
>> between drivers is unnecessarily complex for such a simple feature,
>> reimplement the poweroff functionality in the main MFD driver. While at
>> it, add support for the newer SC2730 PMIC and its hardware reset
>> register.
>>
>> Reboot is special because it requires storing the reboot mode. Move the
>> existing code for this from the SPI bus driver to the MFD driver.
>>
>> [1]: 
>> https://lore.kernel.org/all/20251002025344.GA2958334-robh@kernel.org/
>>
>> Signed-off-by: Otto Pflüger <otto.pflueger@...cue.de>
>> ---
>
> Overall, it looks reasonable to me, but I cannot test your patchset 
> right now due to the lack of hardware. Cixi (who is from Unisoc), 
> could you help test this patchset? Thanks.

the patchset test reboot function on ums512 is ok.

Tested-by: Cixi Geng <cixi.geng@...ux.dev>